Intermittent volcanic activity detected in the Von Kármán crater on the farside of the Moon

Abstract

Sensitive to permittivity differences, lunar penetrating radar (LPR) can detect stratification due to material property differences in a medium. We examined the subsurface structures of Von Kármán crater within the South Pole-Aitken (SPA) basin on the farside of the Moon using LPR data obtained by the Chang'E-4 mission. Various distinct strata with depth are clearly recognized, consistent with multiple periods of intermittent lava flows, paleo-regolith, and crater ejecta. Numerous concave and arc shape structures observed at various depths are consistent with buried craters and broken rocks, indicating that the ancient lunar surfaces which are currently buried by up to 30 m deep in Von Kármán, as well as the current surface, suffered numerous impacting events. An imaged subsurface thick paleo-regolith infers a quiescent period with low volcanic activity within the Von Kármán crater. Following the quiescent period (shallower in the profile), a relatively young period of volcanism in the Von Kármán crater is inferred. The mapped stratigraphy and chronology of these events present a self-consistent history of the Von Kármán crater within the SPA, which suggests connections to events on the lunar nearside.